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US 5,636,356 AGranted
Disk array with original data stored in one disk drive and duplexed data distributed and stored in different disk drives
AssigneeHitachi, Ltd.
InventorsHitoshi Kakuta, Toyohiko Kagimasa, Yoshifumi Takamoto, Atsushi Tanaka
Life of this patent
Estimating the term…
Abstract
A drive unit connected to a disk control unit of a disk array has a logical group formed of a plurality of drives. In the logical group, both original data and duplexed data of the original data are stored. The original data and the duplexed data thereof are stored in different drives. When a plurality of data stored in one drive are to be read, the original data or the duplexed data thereof are read in parallel from the different drives.
Claims35
A disk array comprising:
- (a) a plurality (m;
- m>3) of disk drives;
- and
- (b) a disk control unit for controlling writing of data to said disk drives and reading of data from said disk drives;
- said disk control unit including;
- (b1) determining means for determining a plurality of area pairs each including an area for original data and an area for duplexed data of the original data, among a plurality of areas included in said plurality of disk drives,
- said area pairs being determined such that an area for original data and an area for duplexed data both belonging to a same area pair are located in different respective disk drives, and such that of a set of n area pairs (where 2.ltoreq.n.ltoreq.m-1) which have their areas for original data on a common disk drive, the corresponding areas for duplexed data are distributed in one-to-one correspondence across each of n other drives;
- (b2) means for writing data to be written into said plurality of disk drives both into one area for original data and another area for duplexed data belonging to a same one area pair among said plurality of area pairs as determined, respectively;
- (b3) means for selecting data read areas each constituted by a plurality of areas which are stored on different disk drives and which hold either the original data or the duplexed data of different area pairs to be read from said plurality of disk drives, said plurality of data being greater than two;
- and
- (b4) means for reading in parallel the plurality of data from the plurality of detected areas.
8 more elements
A disk array comprising:
- (a) a plurality (m;
- m>3) of disk drives;
- and
- (b) a disk control unit for controlling writing of data to said disk drives and reading of data from said disk drives;
- said disk control unit including;
- (b1) means for determining a first plurality of area pairs each including an area for original data and an area for duplexed data of the original data, among a plurality of areas included in said plurality of disk drives,
- said area pairs being determined such that an area for original data and an area for duplexed data both belonging to a same area pair are located in different respective disk drives, and such that of a set of n area pairs (where 2.ltoreq.n.ltoreq.m-1) which have their areas for original data on a common disk drive, the corresponding areas for duplexed data are distributed in one-to-one correspondence across each of n other drives;
- (b2) means for writing data to be written into said plurality of disk drives both into one area for original data and another area for duplexed data belonging to a same one area pair among said plurality of area pairs as determined, respectively;
- (b3) means for determining a second plurality of area pairs each including one of a plurality of areas included in one of said plurality of disk drives as an area for original data or for duplexed data, when a fault occurs in said one disk drive;
- (b4) means for determining a third plurality of areas included in different ones of the plurality of determined area pairs and belonging to different ones of said plurality of disk drives other than said one disk drive;
- (b5) means for reading in parallel a plurality of data stored in the plurality of determined areas;
- and
- (b6) means for serially writing the plurality of read data to an alternative disk drive to be used in place of said one disk drive.
10 more elements
A disk array comprising:
- (a) a plurality (m;
- m>3) of disk drives;
- and
- (b) a disk control unit for controlling writing of data to said disk drives and reading of data from said disk drives;
- (b1) means for determining a first plurality of area pairs each including an area for original data and an area for duplexed data of the original data, among a plurality of areas included in said plurality of disk drives,
- said area pairs being determined such that an area for original data and an area for duplexed data both belonging to a same area pair are located in different respective disk drives, and such that of a set of n area pairs (where 2.ltoreq.n.ltoreq.m-1) which have their areas for original data on a common disk drive, the corresponding areas for duplexed data are distributed in one-to-one correspondence across each of n other drives;
- (b2) means for allocating plural ones of the plurality of determined area pairs to a logical address specified by a host device;
- (b3) means for writing data to be written into said plurality of disk drives into one area for original data and another area for duplexed data both belonging to one of the plurality of area pairs as determined;
- (b4) means for determining a second plurality of area pairs each including one of a plurality of areas included in one of said plurality of disk drives as an area for original data or for duplexed data, when a fault occurs in said one disk drive;
- (b5) means for determining a third plurality of areas included in different ones of the plurality of determined area pairs and belonging to different ones of said disk drives other than said one disk drive;
- (b6) means for sequentially reading a plurality of data stored in the plurality of determined areas;
- (b7) means for sequentially writing the plurality of read data into an alternative disk drive to be used in place of said one disk drive;
- (b8) means responsive to a data read request issued from a host device after occurrence of the fault for selecting an area belonging to one of said other disk drives, among an area for original data and another area for duplexed data both belonging to an area pair allocated to a logical address specified by the read request to said allocating means;
- and
- (b9) means for reading data from the selected area in parallel to writing of the plurality of data into said alternative disk drive by said data writing means.
12 more elements
A disk array comprising:
- (a) a plurality (m;
- m>3) of disk drives;
- and
- (b) a disk control unit for controlling writing of data to said disk drives and reading of data from said disk drives;
- said disk control unit including:
- (b1) means for determining a plurality of area pairs each including an area for original data and an area for duplexed data of the original data, among a plurality of areas included in said plurality of disk drives,
- said area pairs being determined such that an area for original data and an area for duplexed data both belonging to a same area pair are located in different respective disk drives, and such that of a set of n area pairs (where 2.ltoreq.n.ltoreq.m-1) which have their areas for original data on a common disk drive, the corresponding areas for duplexed data are distributed in one-to-one correspondence across each of n other drives;
- (b2) means for writing data to be written into said plurality of disk drives both into a first area for original data and a second area for duplexed data belonging to a common area pair among said plurality of area pairs as determined, respectively;
- (b3) means for detecting a pair of said plurality of areas each holding data to be read from said plurality of disk drives as original data or duplexed data;
- and
- (b4) means for reading the data from one area of the detected pair of areas.
8 more elements
Dependencies are inferred from the claim text.